Identifying Cardiomyopathy Genes in Mice and Drosophila

描述（由申请方提供）：钙调神经磷酸酶是一种钙激活蛋白磷酸酶，对于心脏肥大表型的形成是必需的，也是充分的。在哺乳动物中，活化T细胞核因子（NFAT）转录因子的钙调神经磷酸酶依赖性去磷酸化导致肥大基因的诱导。相反，果蝇不含钙调神经磷酸酶调节的NFAT亚型，这表明存在NFAT独立机制的想法。事实上，另一种转录因子，肌细胞增强因子2（MEF 2），也涉及钙调神经磷酸酶介导的心脏肥大。在这种竞争性的更新，我们建议在果蝇进行缺陷和EMS诱变筛选，以确定新的NFAT-独立的增强子和抑制基因的钙调神经磷酸酶信号通路。为了实现这一目标，我们将使用Sullivan和Rubin以及Gaubrski和Schulz进行的筛选中已经获得的信息，他们已经确定了果蝇基因组的大区域，这些区域在由组成性活性钙调磷酸酶（CanAAct）敏化的果蝇筛选中充当抑制子和增强子位点。 因此，我们假设钙调神经磷酸酶介导的心脏肥大可以通过非NFAT依赖性途径发展，并且果蝇中的遗传筛选将鉴定诱导心脏肥大的新分子机制。我们提出以下具体目标：目标1。在果蝇中鉴定钙调神经磷酸酶诱导的肥大信号的新抑制基因。NFAT-独立的钙调磷酸酶信号转导基因将通过使用表达心脏特异性CanAAct的致敏果蝇对先前绘制的抑制基因座进行缺陷筛选来鉴定。目标2.鉴定果蝇中钙调神经磷酸酶诱导的肥大信号的新增强子基因。NFAT非依赖性钙调磷酸酶信号转导基因将通过使用表达心脏特异性CanAAct的致敏果蝇对先前映射的增强子位点进行缺陷筛选来鉴定。目标3.鉴定果蝇EMS诱变诱导的钙调神经磷酸酶诱导的肥大信号的新型遗传修饰剂。EMS化学诱变筛选在表达肌动蛋白- CanAAct的致敏果蝇中诱导整个果蝇基因组的突变。我们预计，拟议的调查将确定新的基因和途径，导致心脏肥大，并将更好地定义钙调神经磷酸酶在肥大过程中的作用。此外，拟议的研究将导致治疗人类心脏肥大和心力衰竭的新靶点。

DESCRIPTION (provided by applicant): Calcineurin is a calcium-activated protein phosphatase that is both necessary and sufficient for the development of a cardiac hypertrophic phenotype. In mammals, calcineurin-dependent dephosphorylation of nuclear factor of activated T cells (NFAT) transcription factors lead to the induction of hypertrophic genes. In contrast, Drosophila do not contain calcineurin-regulated isoforms of NFAT suggesting the idea that NFAT-independent mechanisms exist. Indeed, another transcription factor, myocyte enhancer factor 2 (MEF2), has also been implicated in calcineurin-mediated cardiac hypertrophy. In this competing renewal we propose to carry out a deficiency and EMS mutagenesis screen in Drosophila to identify novel NFAT-independent enhancer and suppressor genes of the calcineurin signaling pathway. To accomplish this goal we will use information already available from screens performed by Sullivan and Rubin and Gajewski and Schulz who have identified large regions of fly genome that act as suppressor and enhancer loci in a Drosophila screen sensitized by constitutive active calcineurin (CanAAct). Accordingly, we hypothesize that calcineurin-mediated cardiac hypertrophy can develop through an NFAT-independent pathway, and that a genetic screen in the fly will identify new molecular mechanisms that induce cardiac hypertrophy. We propose the following specific aims: Aim 1. Identify novel Suppressor genes of Calcineurin-induced hypertrophic signaling in Drosophila. NFAT-independent calcineurin signaling genes will be identified by a deficiency screen of previously mapped suppressor loci using a sensitized fly expressing cardiac-specific CanAAct. Aim 2. Identify novel Enhancer genes of Calcineurin-induced hypertrophic signaling in Drosophila. NFAT-independent calcineurin signaling genes will be identified with by a deficiency screen of previously mapped enhancer loci using a sensitized fly expressing cardiac-specific CanAAct. Aim 3. Identify novel genetic modifiers of Calcineurin-induced hypertrophic signaling induced by EMS mutagenesis in Drosophila. EMS chemical mutagenesis screen to induce mutations across the entire Drosophila genome in a sensitized fly expressing actin- CanAAct. We anticipate that the proposed investigation will identify novel genes and pathways that lead to cardiac hypertrophy and will better define the role of calcineurin in the hypertrophic process. Furthermore, the proposed studies will lead to new targets to treat cardiac hypertrophy and heart failure in humans.